1. Field
Example embodiments of the following description relate to an image forming apparatus, a printing control terminal apparatus, and an image forming method thereof, and more particularly, to an image forming apparatus, a printing control terminal apparatus, and an image forming method thereof, which can perform color dropout.
2. Description of the Related Art
In order to acquire only necessary information in a document processing system, which scans and stores documents having a form of a table type, or which processes information additionally input to a form document, it is desirable to eliminate a table style existing in the form document or a background having a specified color. Such requirements have been gradually increased in business environments, in which a large number of form documents are used, such as insurances, banks, or government and public offices.
In general, a method of eliminating designated colors from a color-scanned image may include a method using optical filters and a method using digital image processing. The method of implementing dropout using optical filters of sensors has the drawback in that it is difficult to adjust the optical filter parameters of the optical filters to match nonstandard colors and the optical filters cannot be used with multiple-color dropout. Accordingly, various digital processing methods for performing pixel-unit processes with a color space converted or maintained as it is have been devised.
If one color is simply designated and eliminated when a document form is removed using the above-described dropout methods in the related art, important information having a color that is similar to the color of the form may also be removed. In order to improve this, a process for enabling a user to select dropout colors, among colors included in an image and to select color dropout sensitivities as in Equation (1) below has been devised.Grayscale1=0.299*Red+0.587*Green+0.114*BlueGrayscale2=0.333*Red+0.333*Green+0.333*BlueDropoutRed=1*Red+0*Green+0*BlueDropoutGreen=0*Red+1*Green+0*BlueDropoutBlue=0*Red+0*Green+1*Blue  (1)
However, this process also has a problem in that the selection of the color dropout sensitivity of the scanned image is not performed through reflection of the scanner characteristics, and thus, the colors that constitute the document form cannot be accurately eliminated.
Further, a method for removing values of other channels that do not correspond to the primary colors through adjustment of weight values of respective channels, as in Equation (2) below, has been devised.DropoutMagenta=0.5*Red+0*Green+0.5*BlueDropoutCyan=0*Red+0.5*Green+0.5*BlueDropoutYellow=0.5*Red+0.5*Green+0*Blue  (2)
Although the color dropout through the above-described weight values by colors achieves good performance in eliminating unmixed colors of RGB or secondary colors through combinations of RGB, there is a problem in the color dropout performance due to the fact that colors expressed on a general manuscript are diverse colors which are not divided into unmixed colors of RGB and secondary colors through combinations of RGB. Further, another problem is due to the fact that the range or sensitivity of the colors to be eliminated cannot be adjusted.
In order to solve these problems, a process for eliminating color by enabling a user to select a specified color and its sensitivity has been proposed as a process for solving the problems.
However, it is troublesome for a user to select the dropout color. Further, if a user selects a place that is not the form by mistake due to, for example, a complicated form or thin lines, or if the selection of the color sensitivity is not correct, even though a desired color has been selected, the color dropout with an accuracy desired by the user cannot be performed.